This invention relates generally to task lights for locally illuminating and particularly to an improved task light which may be conveniently and economically calibrated to uniformly illuminate an entire work area when positioned relatively close thereto.
Individually operated task lights for locally illuminating work areas in a larger room permits dimming the overall ceiling illumination of the room thereby to conserve energy. Modern office furniture defines specific work areas in larger rooms and as currently constructed includes desks and tables many of which include integral cabinets or bookshelves positioned above and to the rear portion of the desk or table yet within reach of a worker sitting at the desk or table. Also, many of these desks and tables include vertical rear closure walls which frequently serve as tack boards.
Work areas which include portions thereof positioned below low overhanging cabinets or shelves require uniform, shadow free illumination throughout the entire work area. While it is convenient and is currently the practice to mount the task light on the underside of such overhanging cabinets or bookshelves, when so mounted the task light is relatively close to the underlying work area, in the order of two feet or less above the horizontal surface of the desk or table. Uniform illumination, free of glare and reflections, of an entire work area which may include horizontal and vertical surfaces located below overhanging shelves by a light mounted relatively close to the work area presents a problem to be solved.
Heretofore, prismatic lenses, reflectors and polarizing baffles have been proposed in connection with task lights to suitably illuminate portions of an entire work area. Also, a cylindrical filter arranged for rotation around an elongated fluorescent bulb has been employed to vary the brightness of illumination of a work area or a part thereof as desired by an individual.
Applicant has found that uniform, glare and reflection free illumination of an entire work area may be economically achieved when the task light is mounted relatively close to the work area. To accomplish this applicant has provided a task light having an elongated fluorescent bulb extending across the work area with a wide, flat and elongated prismatic lens adjacent the bulb for distributing light over the entire work area and in providing a transparent sheet between the lens and bulb having calibrated areas of various degrees of translucency to variously diminish the intensity of certain incident light rays and thereby effect uniform and reflection free illumination of an entire particular work area.